Add palloc_extended for frontend and backend.

This commit also adds pg_malloc_extended for frontend. These interfaces
can be used to control at a lower level memory allocation using an interface
similar to MemoryContextAllocExtended. For example, the callers can specify
MCXT_ALLOC_NO_OOM if they want to suppress the "out of memory" error while
allocating the memory and handle a NULL return value.

Michael Paquier, reviewed by me.

diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c
index e2fbfd420b661bdcc88b9bcb023414425fb46b8c..c42a6b6005639e2a53f27f5da2e9db4b430318a1 100644 (file)
--- a/src/backend/utils/mmgr/mcxt.c
+++ b/src/backend/utils/mmgr/mcxt.c
@@ -864,6 +864,43 @@ palloc0(Size size)
        return ret;
 }
 
+void *
+palloc_extended(Size size, int flags)
+{
+       /* duplicates MemoryContextAllocExtended to avoid increased overhead */
+       void       *ret;
+
+       AssertArg(MemoryContextIsValid(CurrentMemoryContext));
+       AssertNotInCriticalSection(CurrentMemoryContext);
+
+       if (((flags & MCXT_ALLOC_HUGE) != 0 && !AllocHugeSizeIsValid(size)) ||
+               ((flags & MCXT_ALLOC_HUGE) == 0 && !AllocSizeIsValid(size)))
+               elog(ERROR, "invalid memory alloc request size %zu", size);
+
+       CurrentMemoryContext->isReset = false;
+
+       ret = (*CurrentMemoryContext->methods->alloc) (CurrentMemoryContext, size);
+       if (ret == NULL)
+       {
+               if ((flags & MCXT_ALLOC_NO_OOM) == 0)
+               {
+                       MemoryContextStats(TopMemoryContext);
+                       ereport(ERROR,
+                                       (errcode(ERRCODE_OUT_OF_MEMORY),
+                                        errmsg("out of memory"),
+                                        errdetail("Failed on request of size %zu.", size)));
+               }
+               return NULL;
+       }
+
+       VALGRIND_MEMPOOL_ALLOC(CurrentMemoryContext, ret, size);
+
+       if ((flags & MCXT_ALLOC_ZERO) != 0)
+               MemSetAligned(ret, 0, size);
+
+       return ret;
+}
+
 /*
  * pfree
  *             Release an allocated chunk.

diff --git a/src/common/fe_memutils.c b/src/common/fe_memutils.c
index 345221e13179626aa49013c0484c0a0d68230d56..527f9c8a6bc91b78196dafcfef920f918db6bf6a 100644 (file)
--- a/src/common/fe_memutils.c
+++ b/src/common/fe_memutils.c
@@ -19,8 +19,8 @@
 
 #include "postgres_fe.h"
 
-void *
-pg_malloc(size_t size)
+static inline void *
+pg_malloc_internal(size_t size, int flags)
 {
        void       *tmp;
 
@@ -28,22 +28,37 @@ pg_malloc(size_t size)
        if (size == 0)
                size = 1;
        tmp = malloc(size);
-       if (!tmp)
+       if (tmp == NULL)
        {
-               fprintf(stderr, _("out of memory\n"));
-               exit(EXIT_FAILURE);
+               if ((flags & MCXT_ALLOC_NO_OOM) == 0)
+               {
+                       fprintf(stderr, _("out of memory\n"));
+                       exit(EXIT_FAILURE);
+               }
+               return NULL;
        }
+
+       if ((flags & MCXT_ALLOC_ZERO) != 0)
+               MemSet(tmp, 0, size);
        return tmp;
 }
 
+void *
+pg_malloc(size_t size)
+{
+       return pg_malloc_internal(size, 0);
+}
+
 void *
 pg_malloc0(size_t size)
 {
-       void       *tmp;
+       return pg_malloc_internal(size, MCXT_ALLOC_ZERO);
+}
 
-       tmp = pg_malloc(size);
-       MemSet(tmp, 0, size);
-       return tmp;
+void *
+pg_malloc_extended(size_t size, int flags)
+{
+       return pg_malloc_internal(size, flags);
 }
 
 void *
@@ -100,13 +115,19 @@ pg_free(void *ptr)
 void *
 palloc(Size size)
 {
-       return pg_malloc(size);
+       return pg_malloc_internal(size, 0);
 }
 
 void *
 palloc0(Size size)
 {
-       return pg_malloc0(size);
+       return pg_malloc_internal(size, MCXT_ALLOC_ZERO);
+}
+
+void *
+palloc_extended(Size size, int flags)
+{
+       return pg_malloc_internal(size, flags);
 }
 
 void

diff --git a/src/include/common/fe_memutils.h b/src/include/common/fe_memutils.h
index db7cb3e33188e267130ea20ec89a7bf087b5ec29..51f12eb8251058442541350569031bfd32ba47c6 100644 (file)
--- a/src/include/common/fe_memutils.h
+++ b/src/include/common/fe_memutils.h
@@ -9,10 +9,23 @@
 #ifndef FE_MEMUTILS_H
 #define FE_MEMUTILS_H
 
-/* "Safe" memory allocation functions --- these exit(1) on failure */
+/*
+ * Flags for pg_malloc_extended and palloc_extended, deliberately named
+ * the same as the backend flags.
+ */
+#define MCXT_ALLOC_HUGE                        0x01    /* allow huge allocation (> 1 GB)
+                                                                                * not actually used for frontends */
+#define MCXT_ALLOC_NO_OOM              0x02    /* no failure if out-of-memory */
+#define MCXT_ALLOC_ZERO                        0x04    /* zero allocated memory */
+
+/*
+ * "Safe" memory allocation functions --- these exit(1) on failure
+ * (except pg_malloc_extended with MCXT_ALLOC_NO_OOM)
+ */
 extern char *pg_strdup(const char *in);
 extern void *pg_malloc(size_t size);
 extern void *pg_malloc0(size_t size);
+extern void *pg_malloc_extended(size_t size, int flags);
 extern void *pg_realloc(void *pointer, size_t size);
 extern void pg_free(void *pointer);
 
@@ -20,6 +33,7 @@ extern void pg_free(void *pointer);
 extern char *pstrdup(const char *in);
 extern void *palloc(Size size);
 extern void *palloc0(Size size);
+extern void *palloc_extended(Size size, int flags);
 extern void *repalloc(void *pointer, Size size);
 extern void pfree(void *pointer);
 

diff --git a/src/include/utils/palloc.h b/src/include/utils/palloc.h
index 2cf51298331d18233ac4402e9a2014e516ff999c..9861f0dac738819f7f2642b427ebe9ea29b37878 100644 (file)
--- a/src/include/utils/palloc.h
+++ b/src/include/utils/palloc.h
@@ -76,6 +76,7 @@ extern void *MemoryContextAllocExtended(MemoryContext context,
 
 extern void *palloc(Size size);
 extern void *palloc0(Size size);
+extern void *palloc_extended(Size size, int flags);
 extern void *repalloc(void *pointer, Size size);
 extern void pfree(void *pointer);